Planta Med 2007; 73 - P_339
DOI: 10.1055/s-2007-987119

Psychotropic constituents of Mentha aquatica L.

J Van Staden 1, GI Stafford 1, JP Almqvist 1, 2, SAK Vangsøe 1, 2, HT Olsen 1, 2, SB Christensen 2, A Adsersen 2, AK Jäger 2
  • 1Research Centre for Plant Growth and Development, School of Biological and Conservation Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa
  • 2Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, 2 Universitetsparken, 2100 Copenhagen O, Denmark

Mentha aquatica L. is used in Zulu traditional medicine as treatment against colds, respiratory problems and as protection against evil spirits1. It is a perennial herb growing in marshes and damp places from the South-western Cape to tropical Africa and Europe. Six extracts of varying polarity of Mentha aquatica L. were tested in a photometric peroxidase linked MAO bioassay. The 70% ethanol extract gave highest inhibitory activity. (S)-Naringenin was isolated from the extract by bioassay guided fractionation using VLC and preparative TLC. The structure of the compound was verified by 1H, 13C and DEPT NMR and measurement of the optical rotation. The IC50 values for MAO inhibition by naringenin were 342±33µM for the rat liver mitochondrial fraction, 955±129µM for MAO-A and 288±18µM for MAO-B. The ethanolic leaf extract has previously shown strong affinity to the GABA-benzodiazepine receptor1. Viridiflorol from the essential oil and (S)-naringenin from an ethanolic extract was isolated by bioassay-guided fractionation using the 3H-Ro 15–1788 (Flumazenil) GABA-benzodiazepine receptor binding assay. Viridiflorol had an IC50 of 0.19M and (S)-naringenin of 2.6 mM.

References: [1] Pooley E. (2005) A field guide to wild flowers of KwaZulu-Natal and the Eastern Region. Natal Flora Publications Trust. Durban, p.424. [2] Stafford GI et al. (2005) J Ethnopharm. 100: 210–215.